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Full text of "Text Book Of Mechanical Engineering"

CHAPTER IV.
SMITHING  AND  FORGING.

WROUGHT iron is formed into the required shape by drawing
down, and bending while hot; but if there should be insufficient
"' stuff,' or if it should be more difficult to entirely finish by
drawing down, recourse is had to welding.

The working of de-carbonised iron may be best treated undei
two heads, smithing and forging.    The first includes the making
| : i                     of  such   smaller   objects  as   can   be   conveniently   done    at

a smith's fire, while the second term may bd applied to the
shaping of all articles that require heating in a close furnace, and
finishing under a heavy steam hammer. In either case the result
is denominated a forging.

l| ;                   •                                  THE SMITHY.

«1 ,                            We will first consider shortly the plant and tools employed by

11 ',            •          the smith.

The Hearth,—This is represented in Fig. 92. A is a sectional
elevation, and B a front view. It is necessary to explain here that
the smith may arrange his coal on the hearth in two distinct ways,
the one being called an ' open' fire, and the other a * stock ' fire.

||                         The hearth shown in Fig. 92 is by Messrs. Handyside, and is ofi

iron throughout. It is only adapted for i open ' fire working,
being short in length from a to b. a is the tuyere or blast nozzle,
constantly surrounded by water contained in the tank ^ so as to
avoid burning at the outlet, or the accumulation of caked slag.
The work to be heated is placed in the hollow portion of the
hearth surrounded by coal, and as the coal burns away more is
supplied from the hillock £. It will then be seen that there is noi
special difficulty in arranging the coal for ' open * fire working.!

:( I                        ' Stock' working requires a certain amount of trouble in first pre-i

1                           paring the coal, which is usually done first thing every morning.!

After this first preparation it will, however, keep in working order!

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